The present application claims the benefit of U.S. provisional patent application No. 60/242,879, filed on Oct. 23, 2000, the disclosures of which is incorporated herein by reference in its entirety.
This invention relates to methods and apparatus for beaming power from one location to another, and in particular to methods and apparatus for beaming power from a power generating station to a remote receiver by using one or more lasers.
Providing power to remotely located devices is problematic. For stationary devices, such as a seismic data collection facility, it may be possible to install power transmission lines. However, this may be prohibitively expensive, as well as environmentally and aesthetically undesirable. For mobile devices, such as aircraft and satellites, the use of power cables is not possible.
A practical means of providing power to such devices is to generate the power locally using photovoltaic systems that use arrays of photovoltaic cells, also called solar cells, to convert energy in the form of sun light into useful electrical energy. Such systems have found widespread use in, for example, satellites. In addition, aircraft are being designed that can stay aloft for extended periods using electricity generated from solar energy.
However, the relatively poor conversion efficiency of photovoltaic cells is a disadvantage when using them to power objects at high altitude or in orbit. The poor conversion efficiency of photovoltaic cells necessitates the use of large arrays of solar cells to produce adequate electrical power for on board equipment. As a result, heavy and complicated mechanisms are needed so that these large photovoltaic arrays can be folded during the launch of a satellite and then deployed when the satellite is on station. In addition, photovoltaic cells become less efficient as they age. Thus, solar arrays for satellites must be designed to provide extra capacity at launch to compensate for lifetime losses in conversion efficiency. The extra array area and the mechanisms needed to deploy the arrays add to the weight of the satellite and, therefore, to the cost of launching the satellite. Because larger photovoltaic arrays require commensurately larger and heavier deployment mechanisms, there is an increased weight penalty for large arrays.
It would, therefore, be desirable to provide methods and apparatus for supplying power to aircraft and satellites that reduce or eliminate the need for folding photovoltaic arrays.
It would be desirable to provide methods and apparatus for extending the useful lifetime of existing satellites.
It would also be desirable to provide methods and apparatus for supplying supplementary power to existing satellites and electric aircraft.
It would also be desirable to provide methods and apparatus for reducing the size of a photovoltaic array required to provide adequate electrical power to a high altitude or space-based platform.
In addition, it would be desirable to provide an efficient and light weight means of providing electrical power to a high altitude or space-based platform.
It would also be desirable to provide methods and apparatus that enable the development of aircraft, satellites, spacecraft, and other vehicles and devices that are more efficiently and economically powered than are current designs.
It is, therefore, an object of the invention to provide methods and apparatus for supplying power to aircraft and satellites that reduce or eliminate the need for folding photovoltaic arrays.
It is also an object of the invention to provide methods and apparatus for extending the useful lifetime of existing satellites.
It is another object of the invention to provide methods and apparatus for supplying supplementary power to existing satellites and electric aircraft.
It is also an object of the invention to provide methods and apparatus for reducing the size of a photovoltaic array required to provide adequate electrical power to a high altitude or space-based platform.
It is an additional object of the invention to provide an efficient and light weight means of providing electrical power to a high altitude or space-based platform.
It is another object of the invention to provide methods and apparatus that enable the development of aircraft, satellites, spacecraft, and other vehicles and devices that are more efficiently and economically powered than are current designs.
These and other objects and advantages of the invention are achieved by using a system of one or more lasers to transmit power from a location where power is readily available to a remote location where power is scarce. The system of lasers transmits optical power in the form of laser beams in sufficient quantities to be useful for various purposes at the receiving platform, such as powering equipment, propelling vehicles, and other power consuming uses. A beam direction and guidance system maintains the beam upon the power-receiving device.